In order to create a Google Account without signing up for Gmail service, visit https://accounts.google.com/signup and pick "I prefer to use my current email address" option. After filling the form and confirming email, you can then add that newly created Google Account to each of your Search Console services.

Go to http://accounts.google.com/signin/usernamerecovery and enter any email accounts or phone numbers that you've had for a while and which may have been used as recovery info. The “find your email” page can help you locate any forgotten Google accounts.

A Google Account gives you Google-wide access to most Google products, such as Google Ads, Gmail, and YouTube, using the same username and password.